President Donald Trump is much more vulnerable and the Republican Party has "kind of lost its mojo," veteran political strategist Chuck Gabriel told CNBC on Wednesday.
"The holy grail of tax relief, tax reform, did nothing" for the GOP, the president of policy research and political forecasting firm Capital Alpha said on "Power Lunch."
"The heart and soul of the Republican Party going forward is up for grabs," he added.
On Thursday, Democrats will take control of the House away from Republicans but the GOP will retain its majority in the Senate. Meanwhile, the president and congressional Democrats are fighting over funding the government, which resulted in a partial government shutdown 12 days ago.
The shutdown came about after Trump refused to sign spending bills for several federal agencies unless Congress provided $5 billion for his proposed border wall.
Trump is already being condemned by one prominent member of his own party, Mitt Romney. The incoming U.S. senator from Utah and former GOP presidential nominee sharply criticized the president in an essay published Tuesday evening in The Washington Post.
"The appointment of senior persons of lesser experience, the abandonment of allies who fight beside us, and the president's thoughtless claim that America has long been a 'sucker' in world affairs all defined his presidency down," Romney wrote.
He added that "Trump's words and actions have caused dismay around the world."
Gabriel called the timing of Romney's attack very important, coinciding with the reality of the GOP's problems and Trump's stature.
"This is something that wouldn't have happened a year ago. Nobody would have taken on President Trump," Gabriel said. "He is very much more vulnerable and he knows this."
He also thinks Trump's response to Romney was gentler than it would have been several months ago.The president first tweeted Wednesday morning that he would prefer Romney focus on the border wall and other things.
"I won big and he didn't. He should be happy for all Republicans."
Then later in the afternoon, Trump addressed the issue in his first Cabinet meeting of the year. "I wish Mitt could be more of a team player. I'm surprised he did it this quickly," said Trump, who pointed out that he endorsed Romney in the Senate race and the candidate "thanked me very profusely."
"If he fought really hard against President Obama like he does against me, he would have won the election" in 2012, Trump added.
Romney has criticized the president in the past, calling Trump a "fraud" and "phony" in 2016.